Population structure and genetic diversity of the endangered fish black shinner Pseudopungtungia nigra (Cyprinidae) in Korea: a wild and restoration population.

The black shinner Pseudopungtungia nigra Mori, 1935 is an endangered fish endemic to Korea. It lives in the narrow basin of the Geumgang River, Mangyeonggang River, and Ungcheoncheon Stream, which flow into the West Sea of Korea. One population of P. nigra in Ungcheoncheon Stream has been locally exterminated once; it is now inhabiting the upper reaches of the dam through a restoration program. Efforts to identify and understand the genetic structure of these populations are important for conservation planning. Here, we analyzed genetic diversity using 21 microsatellite markers for 9 populations. The mean number of alleles ranged from 4.4 to 8.1, mean allelic richness ranged from 4.6 to 7.8, mean observed heterozygosity ranged from 0.519 to 0.702, and mean expected heterozygosity ranged from 0.540 to 0.763. All groups had recent and historical bottlenecks (P < 0.05, M-ratio < 0.68). Three groups [YD (2019), OC and UC] had significant inbreeding index values, suggesting that they were engaged in inbreeding. We observed a moderate level of genetic differentiation between MG and the rest of the population (FST = 0.135 to 0.168, P < 0.05). The genetic structure exhibited a fitting constant K = 2, along with separation between MG and the remaining populations. With respect to genetic flow, YD (2019), OC, CG, and ND shifted to the UC population (0.263 to 0.278). The genetic flow of each population was transferred only within the population; there was no gene flow among populations, except for the Ungcheoncheon Stream population. This study shows that the Ungcheoncheon Stream population needs conservation efforts to increase its genetic diversity, and the Geumgang River populations needs a conservation plan that considers the possibility of conservation and evolution through gene exchange among the populations.

The complete mitochondrial genome of the endangered freshwater fish Odontobutis obscurus from Korea.

We report the first complete mitochondrial genome of Odontobutis obscurus, which consists of 17,038 bp harboring 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and a control region (D-loop). The overall base composition of the complete genome is A (30.63%), C (28.72%), T (25.70%), G (14.95%). The complete mitogenome of Odontobutis obscurus, most closely related to congeners in the Bayesian inference and maximum likelihood tree, provides a better understanding of the phylogeny of the genus Odontobutis.

The complete mitochondrial genome of the hybrid species Pungtungia herzi (♀) × Pseudopungtungia nigra (♂) from Korea.

This study reports the complete mitochondrial genome of a Pungtungia herzi (♀) × Pseudopungtungia nigra (♂) hybrid. The P. herzi (♀) × P. nigra (♂) mitochondrial genome consists of 16,601 bp with 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a control region (D-loop). The overall base composition of the complete mitochondrial genome is 29.99% A, 26.97% T, 17.11% G, and 25.92% C. In the phylogenetic tree, P. herzi (♀) × P. nigra (♂) is closer to P. herzi than to P. nigra. Obtaining the complete mitogenome of P. herzi (♀) × P. nigra (♂) will provide useful data regarding P. herzi and P. nigra conservation and evolution.

The complete mitochondrial genome of Tachysurus nitidus (Siluriformes: Bagridae) from the Geum river in Korea.

The complete mitochondrial genome of a bagrid catfish, Tachysurus nitidus was completely analyzed by the primer walking method. It was composed of 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a control region with a total length of 16,537 bp. In the phylogenetic tree, using mitochondrial genome of 13 related sequences revealed that T. nitidus (MW451217) of Korea is clustered with T. nitidus (KC822643) of China. This complete mitochondrial genome provides an important resource for reviewing the phylogenetic relationships and taxonomic status of the bagrid species.

Genetic diversity and population structure of the endangered fish Pseudobagrus brevicorpus (Bagridae) using a newly developed 12-microsatellite marker.

BACKGROUND: Pseudobagrus brevicorpus is an endangered species in Korea. The development of genetic markers and genetic information regarding the populations of this species are needed to establish conservation strategies. OBJECTIVE: As part of the conservation of P. brevicorpus, a 12-microsatellite marker was developed using next-generation sequencing (NGS) to provide current genetic population information. METHODS: Microsatellites from P. brevicorpus were identified by NGS analysis. Genetic diversity and genetic structure analysis of six populations (Seojeong Stream [SJ], Gokgang Stream [GK], Jaho Stream [JH], Daega Stream [DG], Nam River [NG], and Deokcheon River [DC]) of P. brevicorpus were conducted using the newly developed microsatellite marker. RESULTS: NGS generated 10,347,578 reads and identified 659,507 simple sequence repeats. Twelve microsatellites were successfully amplified and verified in 30 individuals of P. brevicorpus. The genetic diversity of the six P. brevicorpus populations in terms of the number of alleles ranged from 3.667 to 7.111. All populations except DG deviated significantly from Hardy-Weinberg equilibrium (HWE) at one or more loci. The genetic distances of the six populations showed the closest relationship between the SJ and GK populations (independent Stream populations), and there was a close relationship with the JH population among the Nakdong River. Structure analysis showed that P. brevicorpus is largely divided into two groups. CONCLUSIONS: The developed microsatellite marker will be used to provide basic genetic data of P. brevicorpus. Genetic diversity and structure analysis of the population will provide useful information for conservation management of P. brevicorpus.